1 Charm Review Update on charm mixing Charm semileptonic decay –Analysis of D K* –Analysis…
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Transcript of 1 Charm Review Update on charm mixing Charm semileptonic decay –Analysis of D K* –Analysis…
1
Charm Review
• Update on charm mixing• Charm semileptonic decay
– Analysis of DK*– Analysis of Ds
• Charm 3 body hadronic decay– Isobar model versus K- matrix– Dalitz analysis as probes of new physics
• Excited charm spectroscopy– cu and cd results from Belle and Focus– cs results from Babar/Cleo/Belle/ Focus
• The future of charm physics– B-Factories / Cleo-c / Bes III
Jim Wiss Univ of IllinoisAPS meetingMay 2 , 2004
Apologies for all the important and fascinating results that I had to skip
Featuring results from
2
charm mixing circa 2000
2 sigma hints of mixing at few percent level!
(K) = 409.4 1.34 ps
(KK) =395.4 5.5 ps
CP lifetime comparisons
Time evolution of wrong-sign D* decay
* 0D D
K
3
Mixing circa 2003
Things have come a long way since those heady days...
It will be interesting to see if mixing does occur at the percent level.
4
Dvector decays
H0(q2), H+(q2), H-(q2) are helicity-basis form factors computable by LQCD...
A
22
22 2 2
20
0
sin sin(1 cos )sin
sin sin1( ) (1 cos )sin8 2cos cos2sin cos 2cos
il Vi
l V il Vi
l l Vl V
l VV t
e He H
e Hmq m e H
q HH
H
cc
cmc
q qq q
q qq q
q qq q
q
++ -
---
ì üï ïï ïï ï+ï ïï ï+ï ïï ï= - - - +í ýï ï+ï ïï ï-ï ïï ï+ï ïï ïî þ
right-handed + left-handed +Two amplitude sums over W polarization using D-matrices
22 2
(0)( )1
ii
A
AA qq M
22 2
(0)( )1 V
VV qq M
v 1(0) (0)r V A
2 2 1(0) (0)r A A
Helicity FF are combinations of vector and axial FF
Two numbers parameterize the decay
5
Interference in D+ K*
Yield 31,254
DataMC
K* interferes with S- wave K and creates a forward-backward asymmetry in the K* decay angle with a mass variation due to the varying BW phase
(2002)
F-B
asy
mm
etry
(m K
The S-wave amplitude is about 7% of the K* BW with a 45o relative phase
Focus “K*” signal
The same relative phase as LASS
matches model
-15% F-B asymmetry!
6
K*form factors
1 cos 0.5V
0.5 cos 1V
0.5 cos 0.5V
acoplanarity
Results are getting very precise and more calculations are needed.
7
Ds form factors
Theoretically the Dslform factor should be within 10% of D K*l The rV values were consistent but r2 for Dslwas 2 higher than D K*l
E79
1C
LEO
E65
3
E68
7
BK
S
LMM
S
ISG
W2
0
0.5
1
1.5
2
2.5
3R
V
0
0.5
1
1.5
2
2.5
3
R2
circa 1999
ISG
W2
Focu
s
E79
1C
LEO
E65
3
E68
7 BK
S
LMM
S
0.0
0.5
1.0
1.5
2.0
2.5
3.0
0 1 2 3 4 5 6 7 8 9
RV
But the (2004) FOCUS measurement has consistent r2 values as well!
8
Dalitz plots
“...consistent with a phase space Dalitz distribution.”
The first charm Dalitz analysis – MK1 (1977) D+K
E791 (2002)
CLEO (2001) 0D K
Same state but higher statistics
Lots of structure!
9
What do you learn from Dalitz plots?
D KK
*K K 2KKm
2KKm
2Km
sD KK
*K K
•Bands indicate resonance contributions
•For spinless parents, the number of nodes in the band give you the resonance spin
•Look at the band
•Interference pattern gives relative phases and amplitudes
•Look at the D+ K* band pattern of asymmetry
mm m
m
Aia e M 1 3 13
2 212
(cos )J J r
J
r r r
p p PA
m m im
Isobar model: Add up BW’s with angular factors
broad states
Nearly all charm analyses use the isobar model:
10
Why study charm Dalitz plots?•A valuable source of phase shifts in entangling in B± K ± (K*K)D (discussed in talk of Paras Naik)
•Probes of charm decay mechanismRole of direct annihilation in Ds decay
sD
•Unique mixing probes Time dependent Dalitz fit such as DKs (David Asner)
2 2
22 | | exp( | || |
2 | || | exp( ) cos( cos sin( sin
ex ( ) )pM
A B t x t x
B t
t
A t
s 0
s
0
s
s
B includes K , K
A
and K* contributes to both
(1450),
includes K (980), K (1370),
A Bnd a
f f
Sensitive tosign of x
•New probes of charm CP violation sCleo D sK
-6sSM estimates are 10 for (K )
11
Although used frequently, the isobar model has problems ...
Add two BW ala Isobar model
Add two K matrices
Adding BW violates unitarity
Adding K matrices respects unitarity
When broad resonances overlap you just can’t add Breit-Wigners and respect QM!
Add BW Add K
The Unitarity circle
2 2
m mK Tm s m s im
A real pole in K gives a BW
i i
The isobar amplitude is a sum of BW
M = a angfactors Ti BWe
2*
(single channel for simplicity)
1 2 ;
Unitar
1 Im
y
S iT S S T T
22
2 2
Unitarity can be achieved with
Im
re
1 1
al K
K KT T TiK K
The K and T descriptions are equivalent for a single pole but what happens when several poles contribute??
12
FOCUS D ++- analysis
Observe:
•f0(980)
•f2(1270)
•f0(1500)
Yield Ds+ = 1475
50S/N Ds
+ = 3.41
Several broad and overlapping resonances contribute
Can they fit it using K- matrix based on fits to other data??
Yield DYield D++ = 1527 = 1527 5151
S/N DS/N D++ = 3.64 = 3.64 sD
13
“K-matrix analysis of the 00++-wave in the mass region below 1900 MeV’’ V.V Anisovich and A.V.Sarantsev Eur.Phys.J.A16 (2003) 229
pp
pp
'K K 4
An impressive amount of data is well described in terms of 5 poles
14
D
123
K K
1(1 )iK
K-matrix picture•The Focus amplitude was written as a sum
•F term models S-wave using five virtual states ’•An isobar BW sum represents higher spin resonances•A coherent non –resonant piece is included
1( )I iKF P
known from scattering data (A&S)
describes coupling of resonances to D (fit for
couplings)
0
0
0( ) i
Ji i
ii
FA D a e a e BW
P 4 = 5 '
vector and tensor contributions
15
First K matrix fits to charm Dalitz plotssD
Low mass High mass
18 11.7
+
+2
0 +
(S - wave)π 56.00 ± 3.24 ± 2.08 0(fixed) f (1275)π 11.74 1.90 0.23 -47.5 .7ρ (770)π 30.82 ± 3.14 ± 2.29 -139.4 ±16.5 ± 9.9
decay channel phase (deg)fit fractions (%)
D
Reasonable fits with no retuning of the A&S K-matrix and no need to invoke new resonances (such as (400)) and no NR term
9.243.135.199.23490.231.343.356.6)1450(7.215.27.180.16832.163.249.474.9)1270(
034.117.460.504.87)(
02
ffixedwaveS
decay channel phase (deg)fit fractions (%)
s-wave dominates
16
L=1 charm mesonsOne of few “good” applications of HQET to charm
LSQ Sq Q spin decouples leaving leaving j = LSq as a “good” Q-num
(L=1) (Sq=1/2) j=3/2 and 1/2
cm 1L
3/ 2j
1/ 2j
Splitting might look like this
*0D
1'D
*2D
1D
finitecm
2
0
1
1
Adding SQ=1/2
The SQ acts as a perturbation and creates additional splitting
3/ 2
1/ 2
1
1
*0D
1'D
*2D
1D
0
2
Of course alternative splitting patterns are possible...
The axial states might switch
17
Pion transitions to D and D*
D-wave (narrow)
20 40 Me
32
1
V2
L
-wave (broad)12
2
1
00 MeV2
L S
Transitions are parity + - Hence L is even
Well established
Belle/Focus
Expect 12 such L=1 states
4 cu cd cs
Belle
qD and D* are j 1/ 2
3/ 2j
18
Analysis of mass D spectraD0D+ A very bad fit with just
D2* (2460) + D1(2420) and feed-downs
2
2
* *
*DD
DD
D
*2D*
2 D1D
cl=28% Fit improves dramatically with inclusion of a broad S-wave state
0
1D 'Might be D * or
(both
*
Dor
DD
19
Belle measured the spin 1 states as well
B D
* *2 0 and DD
*B D
*1 1 2, D ' and DD
1 node
2 nodes!
20
L=1 cu and cd results*0D
1'D*2D 1D *
0D
1'D
*2D
1D
2
0
1
1
12
j
32
j
Would be great to resolve this
1'D*0D
Broad widths
Focu
s D
2*0
Bel
le D
2*0
Focu
s D
2*+
Bel
le D
1
0
10
20
30
40
50
60
*2D
1DNarrow widths
21
So on to L=1 cs states.
•Naively expects the same spectroscopy and same pattern of decays to D and D* pionkaon
KK
*
•Two narrow states were seen in DK and D*K transitions. Presumably the jq=3/2 spin 1 and spin 2 states.
•You then expect to see two broad states which were expected to lie above the kaon threshold and decay via s-wave
Are two broad states there???
Ask the experts?
22
New excited Ds states
165 20
A new state DsJ* (2317) was observed by BaBar but with a very small width ( < 7 MeV)
55 10
This was confirmed by CLEO and a new state was discovered DsJ (2463) again with a very small width
These could be the jq=1/2 states but are unexpectedly low in mass.
(2317)
(23
violates Iso
violates parity
viol
17)
(23 ate) s 7 J1
sJ s
sJ s
sJ s
D D
D D
D D
Decays to Ds violate strong symmetries
These states would be narrow if they lie below D K threshold and must decay into Ds
23
What are the DsJ* (2317) and DsJ (2463)?
+ +
( )
351.2 1.7
1 1 1.2 2.1 Me
350.0 1.2
V 0 0
m
•States consistent with JP = 0+ & 1+ given pattern of observed and absent decay modes. They could be the j=1/2 cs, But why the low mass?
•DK molecule? (Barnes/Close/Lipkin)
•4 quark state
•j=1/2 (1+ , 0+ ) states are chiral partners to the (1- 0- ) or (Ds* Ds)(Bardeen/Eichten/Hill)
Bardeen/Eichten/Hill predict a Goldberger-Trieman-like splitting for 1 and 0 states which works for Ds1’ Ds0*
But: 1+ - 1- 0+ - 0- 430 MeV for cu and cd based on Belle measurements
24
Some preliminary cs results from Focus
Another DsJ* (2317) confirmation!
31±7
* *1s sD D K
25
Back to the Future: Charm threshold
“yellow book”1 fb-1MC
U = Emiss - Pmiss
Closing the neutrino in D e events using energy momentum balance
CP violation
Both D’s decay into even CP states
Exploiting quantum coherence
Cleo-c and Bes III: Run at (3770) with high luminosity and a modern detector
mixing
Both D’s decay into the same final state
DoDo, DoK-+
K-
K+
+
Extremely clean events!
U = Emiss - Pmiss
preliminary data (60 pb-1)
Pavlunin
APS Talk
The future of charm is very bright!
26
My Notes
Belle/Focus?
Feed downs
Cleo98?
S and D wave required by parity
Transitions to D0 from L=13 1 can couple via 2 2
L =1 or L =0 but L =1 violates parity
Qj
* *0 0 0 but not since
L is evenD D D
' *1 0 but not since
L is even and L = 0 is fast D D D
*0 0
Feed downs are
D , or ?D D
Transitions to D0 from L=11 1 can couple via 2 2
L =0 or s-wave and go fast
Qj
27
Semileptonic decay as tests of LQCD
(*)KD
c W l
q
s
Apart from form factors, these decays can be computed using perturbation theory
The form factors incorporate hadronic complications and can be calculated with non-perturbative Lattice QCD
28
CP violation in the kspi+pi- Dalitz plot ?0D 0D
-3
-6s
SM estimates run from 10 ( )
to 10 for (K )
2579 D0 2720 D0
0.0140.0220.039 0.034 0.027
stat exp sys model sysCPA
Nov 2003
29
If are not mass eigenstates. Mass eigenstates are(assuming CP conservation)
0 01,2
12
D D D
012 H 021 H 0 0,D D,
Probes of D mixing
110 0
120 0
21 22
H HD Di
H Ht D D
2/jkjkjk imH
Processes which allow mixing appear in H12 and H21.
0 0D D
The time evolution of flavour eigenstates is given by the Schrödinger equation
00 , PP
mx
2
y
Mass and width differences are parametrizedby between D1 and D2 are given by
2 2 2 22
Wrong sign D* decays
( sin cos )2
2
D D
tx
dN
D
t
yy
d
tt
Dx e
D0 K+-
DCSD
oD CAD*D
An alternative probe is to directly compare the lifetime of CP eigenstates or mixed eigenstates.
30
New cu cd L=1 spectroscopyMass D2
*0 D2*+ “D0
1/2” “D+1/2”
Focus03
PDG03BELLE03
2464.5±1.1±1.9
2458.9±2.02461.6± 2.1
± 3.3
2467.6±1.5±0.76
2459±4
2407±21±35
2308± 17 ± 32
2403±14±35
Width
Focus03
PDG03BELLE03
38.7±5.3±2.923±5
45.6± 4.4± 6.6
34.1±6.5±4.225+8
-7
240±55±59
276±21 ± 66
283±24±34
Results roughly agree (1.8 ) between BELLE hep-ex/0307021. FOCUS hep-ex/0312060
538 ± 39
564
509
563
699
520
520
489
259
374
Focus
Kalashnikova 02
Di Pierro (2001)
Ebert et al. 1998
Isgur (1998)
Godfrey and Kokoski (1991)
Godfrey & Isgur (1985)
Eichten et al. (1980)
Barbieri + (76)
De Rujula + (76)
<D1/2>-D
31
Belle measured the spin 1 states as wellM D1 D1 M D1’ D1’
Belle (03) 2421.4 ± 1.5 ± 0.9
23.7 ± 2.7± 4
2427± 6±25
384± 91±74
Cleo (99) 2461 ± 45 290 ± 110
WA 03 2422 ±1.8 18.9 ± 4B D
* *2 0 and DD
*B D
*1 1 2, D ' and DD
1 node
2 nodes!